Obs. : 2016-01-23 Planet Ly alpha (photons/cm^2/sec) Mercury 4.171e+11 Venus 4.055e+11 Earth 3.997e+11 Mars 3.993e+11 Jupiter 4.006e+11 Saturn 4.014e+11 Uranus 4.021e+11 Neptune 4.190e+11 Pluto 4.171e+11